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1. |
Inarticulate brachiopods around the Middle-Upper Ordovician boundary in Västergötland |
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Geologiska Föreningen i Stockholm Förhandlingar,
Volume 108,
Issue 2,
1986,
Page 97-126
LarsE. Holmer,
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摘要:
Inarticulate brachiopods are described from the Upper Viruan (Middle Ordovician) and Lower Harjuan (Upper Ordovician) limestones in Gullhögen quarry, Västergötland, southern Sweden. Sixteen species of inarticulate brachiopods (seven named, six of which are new) are assigned to 14 genera (13 named, one of which is new). The lingulids are treated under open nomenclature. One new acrotretacean genus (Rhinotreta) is described as are the acrotretacean speciesHisingerella tenuis, Conotreta? orbicularis, Veliseptum strictum, Rhinotreta muscularis, Torynelasma? curvata and T.? plana.The stratigraphy of the Middle-Upper Ordovician boundary interval in Västergötland is briefly discussed.
ISSN:0016-786X
DOI:10.1080/11035898609452633
出版商:Taylor & Francis Group
年代:1986
数据来源: Taylor
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2. |
An allochthonous cover in northern Vestranden, Western Gneiss Region, central Norway |
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Geologiska Föreningen i Stockholm Förhandlingar,
Volume 108,
Issue 2,
1986,
Page 127-133
BjörnE. Schouenborg,
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摘要:
The present studies in the northwesternmost part of the Western Gneiss Region, Norway, have demonstrated the existence of previously unknown metasediments and metavolcanics in the Caledonian nappe units. Tectonic and metamorphic breaks as well as lithological differences separate these units from the underlying migmatized gneissic granites and granodiorites. Structural concordance between basement and cover developed as a result of high strain induced by nappe translation. An intense interfolding of basement and cover units postdated the thrusting event. Metamorphic and lithological contrasts in the area are generally preserved. Garnet-biotite thermometry data suggest that the temperatures during post-thrusting metamorphism did not exceed 600°C. Later movements were cataclastic in character and often occurred parallel to older thrust planes.
ISSN:0016-786X
DOI:10.1080/11035898609452634
出版商:Taylor & Francis Group
年代:1986
数据来源: Taylor
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3. |
Textural relations of betechtinite and cobalt pentlandite from Långban, Sweden |
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Geologiska Föreningen i Stockholm Förhandlingar,
Volume 108,
Issue 2,
1986,
Page 135-138
Per Nysten,
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摘要:
Betechtinite and cobalt pentlandite, two minerals new for Långban, were observed coexisting with chalcocite, bornite, sphalerite, galena, and magnetite in a serpentinized skarn. Magnetite occurs in two generations, as euhedral crystals and as fracture fillings. This feature plus the textural relations of sulfides suggest an oxidation at very low temperature. The presence of chalcocite, bornite and minor amounts of native bismuth, and the absence of pyrite indicate a low sulfur activity during crystallization of these sulfides.
ISSN:0016-786X
DOI:10.1080/11035898609452635
出版商:Taylor & Francis Group
年代:1986
数据来源: Taylor
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4. |
A vertebrate bone from the Swedish Paleocene |
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Geologiska Föreningen i Stockholm Förhandlingar,
Volume 108,
Issue 2,
1986,
Page 139-141
Tor Ørvig,
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ISSN:0016-786X
DOI:10.1080/11035898609452636
出版商:Taylor & Francis Group
年代:1986
数据来源: Taylor
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5. |
Rb-Sr isotope data for the Hällefors composite dyke, south central Sweden |
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Geologiska Föreningen i Stockholm Förhandlingar,
Volume 108,
Issue 2,
1986,
Page 143-148
Göran Åberg,
Ricardo Lopez-Montano,
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摘要:
Rb-Sr isotope data of whole-rock samples and apatites from the Hällefors composite dyke, south central Sweden, are presented and discussed. A good fit of several whole-rock points on a 1000 Ma line suggests a homogeneous Rb-Sr composition along the Hällefors dyke. The obtained data (age = 1001 ± 8 Ma, initial Sr ratio = 0.7103 ± 0.0003 and MSWD = 2.84) most likely reflect the low-grade metamorphism or alteration to which the rocks of the dyke were subjected. Several factors, besides sample inhomogencity, are suggested to explain the scattering of the remaining whole-rock samples around the 1000 Ma line: (a) variations inherited from the primary distribution of Sr and Rb in the different components of the dyke, (b) variations due to sampling within more altered domains of the dyke, (c) inheritance of the Sr isotope ratio from the country-rock gneiss. Two apatite separates of different rock types give a mean87Sr/86Sr ratio of 0.70505 ± 0.00043, believed to reflect the initial Sr ratio of the Hällefors system.
ISSN:0016-786X
DOI:10.1080/11035898609452637
出版商:Taylor & Francis Group
年代:1986
数据来源: Taylor
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6. |
Rb-Sr whole-rock dating of the Eringsboda and Klagstorp granites, southern Sweden |
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Geologiska Föreningen i Stockholm Förhandlingar,
Volume 108,
Issue 2,
1986,
Page 149-153
Göran Åberg,
Karl-Axel Kornfält,
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摘要:
Rb-Sr whole-rock dating of the Eringsboda and Klagstorp granites in southern Sweden yields an isochron age of 1358 ± 114 Ma with initial87Sr/86Sr ratio of 0.7064. These values, as well as field and petrographical-geochemical data, are in harmony with similar data for rocks from the Karlshamn granite group, southern Sweden.
ISSN:0016-786X
DOI:10.1080/11035898609452638
出版商:Taylor & Francis Group
年代:1986
数据来源: Taylor
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7. |
A marked change in the stable carbon isotope ratio at the Pleistocene-Holocene boundary in southern Sweden |
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Geologiska Föreningen i Stockholm Förhandlingar,
Volume 108,
Issue 2,
1986,
Page 155-158
Sören Håkansson,
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摘要:
Organic sediments taken from eight south Swedish lakes show a marked decrease in the δ13C values at approximately the Pleistocene-Holocene chronostratigraphic boundary. The result of a survey of different factors influencing the stable carbon isotope ratio in the organic component in lake sediments is presented and discussed for the special case at hand, namely a change from late-glacial to post-glacial environmental conditions for lakes with moderately soft water.
ISSN:0016-786X
DOI:10.1080/11035898609452639
出版商:Taylor & Francis Group
年代:1986
数据来源: Taylor
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8. |
Geochemistry of the Proterozoic Segmon granite, southwestern Sweden |
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Geologiska Föreningen i Stockholm Förhandlingar,
Volume 108,
Issue 2,
1986,
Page 159-166
Kirsten Holme,
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摘要:
The Segmon granite is one of the younger ensialic granites which intruded the Southwestern Gneiss Region of the Baltic Shield. The granite is red, medium-grained and strongly foliated, and has a zircon age of 1249 Ma. The geochemical characterization is based on nineteen rock samples. Even though the analyses show considerably heterogeneous compositions, regular interelement variations among the immobile elements are found. The granite is alkali-calcic and metaluminous. REE analyses show distinctly enriched LREE patterns, less enriched HREE patterns, and strong negative Eu anomalies.
ISSN:0016-786X
DOI:10.1080/11035898609452640
出版商:Taylor & Francis Group
年代:1986
数据来源: Taylor
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9. |
Different types of fossil frost fissures in south Sweden |
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Geologiska Föreningen i Stockholm Förhandlingar,
Volume 108,
Issue 2,
1986,
Page 167-175
Gunnar Johnsson,
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摘要:
Fossil frost fissures are frequent in southern Sweden. Except those formed in an intermorainic position they are all caused by the periglacial environment at the time of deglaciation. The different types of these fossil frost fissures are described, and examples are taken from different areas in southern Sweden.
ISSN:0016-786X
DOI:10.1080/11035898609452641
出版商:Taylor & Francis Group
年代:1986
数据来源: Taylor
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10. |
Åke Johansson |
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Geologiska Föreningen i Stockholm Förhandlingar,
Volume 108,
Issue 2,
1986,
Page 176-176
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ISSN:0016-786X
DOI:10.1080/11035898609452642
出版商:Taylor & Francis Group
年代:1986
数据来源: Taylor
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